Efficient and durable uranium extraction from uranium mine tailings seepage water via a photoelectrochemical method

Summary Current photocatalytic uranium (U) extraction methods have intrinsic obstacles, such as the recombination of charge-carriers, and the deactivation of catalysts by extracted U. Here we show that, by applying a bias potential on the photocatalyst, the photoelectrochemical (PEC) method can address these limitations. We demonstrate that, owing to efficient spatial charge-carriers separation driven by the applied bias, the PEC method enables efficient and durable U extraction. The effects of multiple operation conditions are investigated. The U extraction proceeds via single-step one-electron reduction, resulting in the formation of pentavalent U, which can facilitate future studies on this often overlooked U species. In real seepage water the PEC method achieves an extraction capacity of 0.67 gU m-3∙h-1 without deactivation for 156 h continuous operation, which is 17 times faster than the photocatalytic method. This work provides an alternative tool for U resource recovery and facilitates future studies on U(V) chemistry.